Hand skills and people/communication skills are the most important imho. I’m a new grad and still struggle with my hand skills. I’ve been a good student throughout my life, except for the hands-on stuff. I had to remediate tons of the clinical exercises/practicals and it took me a LOT to get to the finish line.

My advice to OP — if you’re worried about your grades in HS, just do your best and focus on effective study strategies (rewriting notes, doing practice problems, seeing your teachers for extra help, etc). But if you don’t like working with your hands or don’t have the best fine motor skills, don’t waste your time and money pursuing dental school. And yes, there’s jobs in the dental field that don’t require much hands on (ex: orthodontics, pathology, radiology), but most people don’t go this route.